Real Gases: Crash Course Chemistry #14

Hank bursts our ideal gas law bubble, er, balloon, and brings us back to reality, explaining how the constants in the gas law aren't all that constant; how the ideal gas law we've spent the past two weeks with has to be corrected for volume because atoms and molecules take up space and for pressure because they're attracted to each other; that Einstein was behind a lot more of what we know today than most people realize; and how a Dutch scientist named Johannes van der Waals figured out those correction factors in the late 19th century and earned a Nobel Prize for his efforts.
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Table of Contents
Constants in the Gas Laws Aren't all that Constant 1:20
The Ideal Gas Law has to be Corrected for Volume and Pressure 3:26
Einstein was the Bomb 5:02
Van Der Waals Equation 9:38
Never Give Up! 10:08
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[@crashcourse]

Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/2SrDulJ

[@izuka]

I love how crash course throws in all the history behind the names of laws and units that Ive been hearing since hight school. I dint know why, but learning about the story behind the equations makes it more exciting, and thus easier for me to understand. Thanks CC!

[@musashi939]

izuka kind of understandable considering how our brain works. Association, association association

[@gobyg-major2057]

izuka high*, didn’t*

[@irenemiller9205]

me to

[@comettrail4024]

Becoming the director of a school = suddenly realizing that you are Dumbledore. Sweet.

[@voldemortsnose7336]

i was gonna say that! but you were three years early lol

[@XPimKossibleX]

the awesome hank green - teaching life advice to teenagers through gas laws.

[@okrish_]

eheheeh

[@HalfBlindProductions]

it's 4:33 am what started out as review for a biology test has turned into a science binge. science is awesome

[@divyaganesh1585]

True

[@wes4zhang]

This video was sponsored by CGP Grey. :P

[@LittleCorns]

THat was the longest analogy ever.

[@talhatariqyuluqatdis]

I was JUST ABOUT TO comment the same thing. :(FFFFffffffffffffffffffffffffffffffffffffffffffffffffffffffuk

[@harshitakanal7411]

indeed looongg

[@dukebozikowski3801]

facts

[@kyoshinka]

And the same goes for gases. 🙂 OF COURSE

[@thechickenman3713]

That caught me off guard

[@BrainBuzzer]

Don't know why, but I am starting to love chemistry. :) Thanks Hank.

[@aasthasharma3820]

then you finally know that you are starting to succeed at life:)

[@BrainBuzzer]

That was temporary. When mybteacher started teaching those new things which are not covered, my life sucks.

[@aasthasharma3820]

look through scishow, I haven't watched their videos much, but it's Hank there too, so it might be helpful

[@maybeinactive]

CGP grey shirt??

[@metadolle8925]

* decides to fall asleep listening to the CC Chem playlist to study for AP Chem finals * * somebody help my soul *

[@hari-krishnakoipallil8436]

I do it all the time'

[@muisho]

oh my god this man is a Living Saint. He explains thats so that I can understand them so much better. Hes actually better than the Chemistry teacher that I had in High School. I can honestly say that my interest in Chemistry is solely from him.

[@MrLouisBrooks]

How did Van der Waals manage to turn into Dumbledore?

[@shingadwyin]

He ate his vegetables and worked hard.

[@Disastermere]

chibidrin According to Spiderman, if you eat your green vegetables, you can be like him, too.

[@diamondgirls3898]

thats cause he is owned by dishy

[@bristolhalle8463]

Magic... O3O

[@rabbitpiet7182]

Yes

[@ka1e_chips]

I watched CC Physics, and then CC Chemistry again, and then wished Hank would host CC Physics.

[@sympleseries]

SAMEEE

[@sakibchowdhury4747]

Correct

[@mujtabasirius]

Same

[@rakshaaiyappan8193]

Shini Somara is a great host too :/

[@joshuarieder2865]

CGP Grey's shirt? That man is as informative as you! And you should continue to become a teacher of any sort!

[@bluehaxor88]

9:54 12 200 kPa - 11 800 kPa =/= 3 000 kPa, but 400 kPa. Unless I missed something or didn't understand the units, there, I think you got this wrong. I'm pretty sure I'm not the first to point this out, though, but I didn't go through the 530+ other comments. Also, I still really love your show, and I'm _so_ excited to vicariously aid in the KZbin education of other viewers by subscribing to you on Subbable (seriously, you're awesome)! :D

[@re1nh4rd7]

Hats off to you for paying attention mate!

[@TheGryffindorer]

Annnnd The Nobel Price for explaining science goes to ... That awesome guy in the Video ! Keep it up ! Man !

[@shawna9807]

When i get to college i am taking every class in science.

[@FirstNameLastName-qt2hz]

hope you don't live in the US

[@erictaylor5462]

Wrong! Adults do live on an allowance. This sum of money is determined by your weekly paycheck minus rent/mortgage, phone bills, gas bills, electric bills, car payments, 401K payments, other money owed payments, and the amount of money given to your kids for their allowance. Any money left is the adult's allowance, which might be less than the kid's allowance, which is sad.

[@erictaylor5462]

Kate Senatskaya This is very true. I'm convinced that having kids cause other things. My sister had her first child when she was 18. By the time she was 25 her hair had gone completely gray. She was forced to start coloring it. My dad was 23 when I was born (first child) and he was well on his way to going bald by 25. I am childless and 44. Not only do I still have a full head of hair It's still dark brown. No gray at all. Most of my friends who are my age who have kids have at least some gray hair and most have a lot. My childless friends don't have any gray.

[@erictaylor5462]

Mads Andreasen I think if you have a child you should take responsibility for it. After all it's YOUR child, your genes, and you have the greatest interest in seeing it become a successful adult. You do you think so much of the child abuse is committed by STEP parents?

[@erictaylor5462]

Mads Andreasen oh yea, SURE ;)

[@shaboatrad4066]

I know it's a stupid comment in the middle of chem,but Hank Green Your smile is pretty nice almost everytime he smiles I smile too! Good job guys the writer has done an amazing job to make it fascinating! Thank you Crashcorse I've learned a lot! !! and good news I am accepted in the Biology Olympiad by Watching crashcorse and finishing all my text books! Tnx A LOT!!

[@aasthasharma3820]

If you want to watch him smile more, then watch vlogbrothers, and pretty much all you will see will be Hank smiling

[@sacchrine_]

02:36 oh my gosh it's Dumbledore! I love Dumbledore!

[@janAlekantuwa]

Love the CGP Grey shirt

[@Calvinatorzcraft]

I guess I'm not the only one

[@somedaymaybeyt4048]

lol...crash course is...AP Chem...FOR DUMMIES lolollolol *actually goes crying in a corner*

[@Perchumovic]

I'm actually surprised by the amount of information that he can communicate in just 10 minutes.

[@matthewsanders6499]

Hank, I want to thank you for this series of videos (which I have been bingeing for the last 2 hours). I've been a professional brewer for a number of years, and recently I decided to enroll at my local college to study biochemistry in order to further my career. I start Chemistry lab work next week. Your sign-off message of never giving up on one's dreams because of the potential that they offer, even for a 30-year old working-class scientist, is just what I needed to hear right now. The cost of tuition is a dear price to a person who works full time, and I hesitated to pay it willingly. But now I find myself resonating strongly with the story of Van Der Waals, old as it is. I have followed SciShow since the early days purely for entertainment, but now you have given me something more than either entertainment or academic knowledge, you have offered me encouragement. Thank you. (P.S. Can you recommend any high-quality Periodic Tables for home use and display? I can see you are a fan!)

[@smacinnes15]

CGP Grey T-shirt!

[@absojake]

I think there is more in the Van der Waals equation than experimental factors. Although it required Physics that accepted molecules, the experimental factors are related to dipole moments of molecules, which can be theoretically calculated.

[@JonathanHilierChannel]

Love CPG grey!!!!!!!!!!!!!!!! nd the shirt, Hank!!!

[@SeanChaos117]

I love how hank is wearing a cgp grey t shirt, because cgp grey also talks about the school thing in hello Internet :0

[@tevincoles5716]

5:35 i want a pump that only does 1 molecule at a time... :)

[@swimkid526]

The segue in the beginning was absolutely pro

[@hansi98]

in order to find out the number of mols you would have to weight the gas, how do you weight a gas that is lighter than air on earth? do you measure the "negative weight" and calculate the mass with the lift?

[@RobJess]

nice CGP Grey tshirt *****

[@CyborgSolar]

I actually understood this..

[@daniellbondad6670]

Visual information goes very well when explaining.

[@GreedyCapybara7]

Well that's the point. He/she asked if you could convert a gas into a liquid by raising the pressure (as opposed to lowering the temperature) and you can because pressure and temperature are proportional in most cases. However in a hypothetical scenario where one might increase the pressure without increasing the temperature there is almost no limit to the amount one could compress something even if it's a gas at room temperature.

[@abeta201]

I'm not sure what you mean. The schwarzschild radius is universal. It varies with the mass of the substance, and is not necessarily associated with fusion. Anything at all that exceeds its own s. radius will always become black hole, no matter what.

[@Azivegu]

indeed, internet based learning channels are desperately needed in a world suffering from The History Channel Effect. CGPgrey, Crash Course and others are excellent channels.

[@bbee6]

Man you do not know the struggle of high school until you do the IB diploma. That shit is cray cray. Speaking of which, these crash courses are fabulous!! Good work!

[@snickydoodle4744]

Crashcourse Chemistry has a very interesting hook in the beginning of the video.

[@brezzyBribri]

Thank you much for these series btw!! used them in bio last year and using now in chem. Love how its explained, u guys are awesome!

[@georginaphelps8287]

In re of the start, my teachers outright say I only need to know half of what they teach us for our GCSEs and that we won't ever use it after those.

[@jengeller9116]

You just helped me soon much for my AP chem test. Thank you!

[@bluefootedboobie100]

We all looked at his left hand after he said he hasn't done any if the raising kids stuff. We all looked for the ring. Don't deny it.

[@lovely-mk4rt]

He has some big hands

[@Roodbeard]

You've already talked more about us dutch people and the Netherlands than John did in Crash Course World History.

[@angelalvarado3893]

would be a great idea to have a crash course of physics explained by Henry from Minute physics, that would be awesome too

[@RainboConnie]

Would you do a video about crude oil and fractional distillation? It would really help with my chemistry revision.

[@Merlmabase]

diggin' the jacket, hank. and damn that was one magnum opus of an introduction

[@马宁唯]

it helps my presentation. Great.

[@jacksoniansonex9235]

That, my friend is a great t-shirt.

[@TacticusPrime]

Yes to the last part.

[@brandonthesteele]

Hank, you have wordlessly convinced me to buy a CGPGrey shirt.

[@andronicus257]

Your confusion is really about maths convention. It's a little counterintuitive, but I'll try to explain. "P" describes the value of the pressure of the "real" gas. (P+n2a/V2) actually describes the pressure of the "ideal" gas; in other words, "n2a/V2" is what you add to the "real" gas to find the "ideal" gas pressure. Notice that at 07.58 the equation begins with (P+n2a/V2), but is rearranged so the correction is subtracted from the opposite side to give the real (lower) pressure value of P.

[@matthewmesa3711]

excellent and encouraging note to end on! much love brother

[@eiryokid77]

Thank you for the sharing. I love to learn through this guys video...

[@corythecreeperplaysmc8464]

PV=nRT is correct since V-nb=V since nb is nobody.

[@Melontree59]

how come the difference between 12200 kPa and 11800 kPa is 3000 kPa?! did I get it wrong or did he make a mistake?

[@Levipaulsen]

I caught this too. I don't know wtf he's talking about. It's 400.

[@timothychin1594]

0:30 Well, Hank is finally going to start raising kids...

[@aasthasharma3820]

ya :) I was just gonna comment the same thing

[@danlmd1]

CGP Grey t-shirt

[@kronosbot5]

I noticed that too. :)

[@arfaiqbal-gv3jd]

what a motivational tale...I'm in tears 👏

[@samrajdwivedi]

Hank Green....! Dude u rock... :D Never on Mars(cuz u like it) i thought Chem would be DAT eaaasy.. :D Yaay

[@lordofedges6487]

Looked a while ago but never found it, anyone know a table or list of a and b values for most gasses?

[@luciabee]

I LOVE THESE SO MUCH

[@mariebondy4977]

I appreciate the GCP Gray T shirt in this video :)

[@KTC88]

GCP Gray? Or CGP Grey?

[@Newbport849]

Marie Bondy You're hot.

[@zarinawillows2347]

The way he talked at 8:20 made me laugh so hard. Now, people are staring at me.

[@awesomesheen]

Loving the new, much more stylish jacket. You look hip Hank!

[@Slithy]

Despite all this, CGPgrey deserves this. He is awesome :D

[@DutchLabrat]

Little history correction: van der Waal did finally get his doctorate at the age of 36 at the university of Leiden. After that he worked as a physics professor in Amsterdam.

[@CaraIsNotFunny]

Excellent! My idea that dogs can speak but are secretly super spies whose dog houses lead to an underground mission control is probably correct! (Sarcasm)

[@GreedyCapybara7]

Solid krypton would just be called solid krypton for the same reason liquid oxygen is called liquid oxygen. On a similar note crystalline carbon should not be called "diamond" if we were to adhere to naming laws consistently but "carbonite" which is something else entirely.

[@IsYitzach]

I was hoping for some isotherms. Van der Waal's equation shows liquid behaviour.

[@Bridgetwitt23]

wish you had been my chemistry teacher back in high school!

[@mikejennette8478]

Love the Cgp grey shirt

[@2012Zyle]

Love the t-shirt, hank!

[@HighMansx]

My HS teacher (Mrs. Witham) taught our class this mnemonic. "P(r)V=NRT" Pronounce it, it's quite ctrchy.

[@sjwimmel]

I like the way you related chemistry to real life. It was actually kind of inspirational, teachers should do that more often.

[@potionriver]

I SAW DUMBLEDORE!!!! 2:36

[@mahmoodmohammed240]

he said that we have to account for the decrease in pressure, and to solve that he added P+na/V. how is it "decreased" if he "adds" to the pressure in the equation, shouldn't he subtract. (i feel like this is a stupid question but i just don't get it so can someone please explain) edit: ok so i get that during the math the + will conver to a (-) and the pressure will decrease but what about the volume, the opposite thing happens and i'm left with the same question.

[@darshanshah378]

heh heh heh at 0:42 the calculator says boobs

[@KTC88]

Subliminal messaging! lol

[@parth1217]

+Darshan Shah hah!

[@rodriamarog]

"Einstein was the bomb" LOL

[@kenneth3192]

What I don't understand is, and maybe I'm wrong, when the calculations of the ideal gas law was first done with a v= 10L, then reduced to 1L, the result was changed by a factor more than just a reduction of a digit in an equation where nothing else had changed. I mean that, even if it is reduced by a digit, the answer should have still been 118 KPA, instead of 122, as we did factor in a & b. I understand the ideal gas equation would have had no effect on it in real life, as the pressure is not extreme, but why did we have to do the real gas equation with 10L at all, then, when it was said to still be 122 kPa? I do love and appreciate these videos, however. Also, when I did the real gas equation, and I could be wrong, my output was 11,899.88, not 11,800 kPa. I would love if someone else corrected me / chimed in on this.

[@Waterdreamer1290]

Hank and I are wearing the same shirt! GGP grey + Hank Green + Crash course + Me ---> a very wonderful chemical equation.

[@NJVorwerck]

lmao his intros. I feel like he has as much fun with them as possible.

[@FakeBlocks]

Say something about the 1821 Greek revolution

[@JimCullen]

They did biology first, and then chemistry. I think the logical next step is that they will do physics. Moving upwards in terms of purity :D

[@dwyt]

Love story's like this! Great work hank :)

[@guyonacomputer1261]

Chemistry is awesome!

[@canoncamacho420]

im not even 12 buti understand and this is great. hank ur the best

[@shubhraagarwal9250]

So well taught!

[@MasterBace]

Yes.

[@josef-namnguyen6884]

Watching this post 2016 and knowing that Hank has tried the whole raising a kid thingie.

[@Sabourok]

Now I'm wondering where we even got the values for a and b for each gas. My head currently hurts from binge watching crash courses and the only thing I'd been able to find so far is a chart of the a and b values for various gases, but I was hoping someone could explain HOW we found those values in the first place or at all.

[@ninadanklesaria6425]

at 0:42 The calculator.. :D

[@bristolhalle8463]

I don't get it XD

[@borisdorofeev5602]

Bewbs

[@emrefarukakay9102]

Wasnt the pressure suppose to be decreased because intermolecular interactions ?

[@MrWhonut]

Henry, I'm looking at you! Hank would also be brilliant.

[@dooitzeyidejong]

They should rather give all students in South Africa a DVD box with this course, much cheaper and much more effective than the current system which is total crap. The level of education is so low, it's not even to be called secondary education.

[@ragnkja]

What Einstein proved was the size, and thus also existence, of atoms.

[@TheGmoney4980]

Would love a FULL episode of Hank,John, & CPG! That would be awsome!

[@saakethcreddy6569]

I didnt understand why we add the corrected pressure to the ideal pressure instead of subtracting it...both the volume and pressure are supposed to decrease in real life but subtraction has only been done for volume and not for pressure..ASAP HELP!!!

[@chiblast100x]

Hank: Most adults rarely have to... live on an allowance... Me: Tell that to my budget, and I suspect that of the rest of the bottom 50% of the economy, after bills. Even more so those who have kids, from everything I know of that matter. An allowance is one of the few things adults foist on kids that will absolutely teach useful life skills without all the risks of learning them out on one's own in the "real world."

[@2menace]

You took the correction factor of nitrogen gas, but shouldn't you like also take in account the oxygen?

[@TrueCourse]

10:27 "Einstein was the bomb." LOL! Sure it wasn't Oppenheimer? XD Thanks so much for contributing all your work for the betterment of all! :)